Purpose: Eosinophilic gastroenteritis (EG), first reported in 1937 by Kaijser, is an extremely rare disorder of unknown etiology characterized by eosinophilic infiltration of one or more layers of gastrointestinal wall. Only around 300 cases of EG have been reported in the literature so far. Eosinophilic ascites (EA) is the most unusual and rare presentation of EG and occurs when the serosa is involved leading to peritoneal inflammation. We report a case of EA which, to our knowledge, is the first case of idiopathic EA in a pregnant patient. A 29-year-old Hispanic female, G5P4, 19 weeks pregnant, with past medical history of gestational diabetes and exercise-induced asthma, was admitted to our institution with complaints of nausea, vomiting, diarrhea and abdominal pain and distention of 7 days duration. Abdominal ultrasound revealed hepatosplenomegaly, dilated portal vein and diffuse ascites. Ascitic fluid analysis revealed RBC 10000/mm3, WBC 6908/mm3, eosinophils 89%, glucose 61 mg/dl, SAAG 1.6. Microbiological studies were negative. CBC showed leukocytosis of 13800/mm3 (N53%, L15%, M3%, E29%, B0.2%). Chem 13, hepatitis panel, ANA, ASMA, lipids, ceruloplasmin and stool studies were all normal. An upper endoscopy revealed eosinophilic esophagitis and eosinophilic gastritis on biopsy. A diagnosis of eosinophilic gastroenteritis with ascites was made and prednisone 20 mg PO daily started. Symptoms improved rapidly and prednisone tapered off gradually after 6 weeks. Clinic follow-up at 3 months revealed complete resolution of her symptoms, ascites and organomegaly. Peripheral eosinophilia also resolved. The rest of the pregnancy was uneventful and she delivered a healthy infant. Diagnostic criteria for EA include presence of gastrointestinal signs and symptoms, eosinophilic infiltration of both serosal layer of gut wall and ascitic fluid in addition to exclusion of other known causes of eosinophilia. Peripheral eosinophilia is seen in 50-90% cases. Around 80% of the cases are associated with atopic disorders and 16% have a positive family history. Although EG is more common in males, EA has predominantly been diagnosed in females. Most common symptoms include abdominal pain (70-100%), diarrhea (45-70%), nausea/vomiting (30-50%), and recurrent ascites (10-20%). Diagnosis requires ascitic fluid eosinophilia, upper endoscopy with biopsy and sometimes omental biopsies. Corticosteroids are the mainstay of therapy. Steroid sparing regimens are montelukast, sodium cromoglycate, ketotifen, mycophenolate mofetil and omalizumab. Prognosis varies from spontaneous resolution to chronic, relapsing remitting course. In the future it would be interesting to see if pregnancy alters the course of this rare disease.